I feel your pain. But realize that he's just recreating the rthyms of marriage with someone else. In a way, it behooves you for him to be with someone else, because it means he leaves you alone. She is merely a transition woman. I know none of this soothes you right now, but it will in the months to come. Besides, I know the best revenge I ever got was when I met my first husbands new gf (10 years younger btw), we formed a surface relationship. She eventually lent to complaining and I waited and waited and then waited for that window of opportunity and then there it was! I said "I'm glad he's using YOUR bathroom for those nuclear BM's now and not mine...good luck with that". I thought my kids were going to pee themselves!